Some Questions about Plasma Screens

1) Do plasma screens suffer "burn -in" from a fixed image, specifically, the logos that every channel now places at the bottom right of the screen? I like the LG 50" plasma [780 P]. There is a more expensive model that claims to reduce the "burn-in" potential, but this model is not available at the big box stores.

2) Will brown-outs fry a plasma screen? Some kid at a big box store said it was necessary to buy a $200- power conditioner/protector to prevent a fried screen. He also claimed that this problem is NOT covered by the warranty.